Figure 3.

PL spectra of solar cells and PL peak energy and integrated PL intensity. (a) PL spectra of the solar cell samples annealed with different temperatures. The laser excitation power is I_L = 0.3 W/cm². (b) PL spectra of the solar cells annealed with different temperatures. The laser excitation power is I_H = 3,000 W/cm². (c) PL peak energy and integrated PL intensity as a function of annealing temperatures under low excitation power I_L. The inset is the PL line width as a function of annealing temperatures. (d) PL peak energy and integrated PL intensity as a function of annealing temperatures under high excitation power I_H. The data obtained from the as-grown material is plotted at 650°C.